Thermal and catalytic conversion of asphaltenes

Asphaltenes isolated from coal liquids and tar sand bitumen have been conve rted thermally and with acid and/or hydrogenation catalysts. The conversion s, based on solubility classes - preasphaltenes, asphaltenes and oil - have been determined for increasing reaction time. The removal of heteroatoms i n each solubility class was also followed with increasing conversion. Gaseo us deuterium was utilized in some studies to follow the extent of exchange reactions. There is a rapid initial conversion at each reaction temperature , and this is followed by a much slower conversion process. The deuterium d istribution in the products suggest that the asphaltene decomposes to produ ce a stable oil molecule and a radical fragment that remains in the asphalt ene solubility range. (C) 2001 Elsevier Science Ltd. All rights reserved.